(a) A person shall not discharge into the atmosphere from any equipment having a maximum heat input rate of more
than 12.5 million kilogram calories (50 million BTU) per hour used to produce steam, for which a permit to build,
erect, install or expand is required after May 7, 1976, air contaminants that exceed the following:

Oxides of nitrogen, expressed as nitrogen dioxide (NO2), calculated at three percent oxygen on a
dry basis averaged over a minimum of 15 minutes, as shown in the following table:

Fuel

Gas

Liquid or Solid

Concentration

125 ppm NOx

225 ppm NOx

When more than one type of fuel is used, the allowable concentration shall be determined by proportioning the
gross heat input and allowable concentration of each fuel.

Combustion contaminants that exceed both of the following two limits:

(A) 5 kilograms (11 pounds) per hour.

(B) 23 milligrams per cubic meter (0.01 gr/SCF) calculated at three percent oxygen on a dry basis averaged over
a minimum of 15 consecutive minutes.

(b) Nothing in this rule shall be construed as preventing the maintenance or preventing the alteration or modification
of existing steam generating equipment which will not increase the mass rate of air contaminant emissions.